Elsmere climate

Elsmere Frost Dates and Growing Season

NOAA 1991-2020 normals for Wilmington Porter Rsch, 6.2 km from Elsmere, elevation 270 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wilmington Porter Rsch. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around April 7 and the first fall freeze around November 4, a growing season of about 209 days.

Median at 36°F
last April 20, first October 24
Median at 32°F
last April 7, first November 4
Median at 28°F
last March 29, first November 15

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FMay 7May 1Apr 27Apr 23Apr 20Apr 17Apr 14Apr 11Apr 6
32°FApr 24Apr 18Apr 13Apr 10Apr 7Apr 5Apr 2Mar 31Mar 26
28°FApr 10Apr 5Apr 2Mar 31Mar 29Mar 26Mar 22Mar 19Mar 13
24°FMar 31Mar 27Mar 24Mar 20Mar 17Mar 14Mar 11Mar 7Mar 1
20°FMar 23Mar 18Mar 14Mar 11Mar 8Mar 5Mar 1Feb 25Feb 19
16°FMar 13Mar 8Mar 4Mar 1Feb 26Feb 22Feb 17Feb 11Feb 4

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FOct 9Oct 14Oct 18Oct 21Oct 24Oct 27Oct 30Nov 2Nov 6
32°FOct 21Oct 27Oct 30Nov 1Nov 4Nov 7Nov 10Nov 13Nov 19
28°FNov 1Nov 6Nov 10Nov 12Nov 15Nov 18Nov 22Nov 27Dec 2
24°FNov 11Nov 17Nov 21Nov 24Nov 28Dec 1Dec 4Dec 9Dec 16
20°FNov 22Nov 29Dec 2Dec 6Dec 10Dec 15Dec 20Dec 25Dec 31
16°FDec 5Dec 11Dec 17Dec 22Dec 26Dec 31Jan 4Jan 8Jan 16

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F204198194190185181177172165
32°F229223217213209205201197189
28°F254247242237232228224220213
24°F278270264259254250245241232
20°F301294288281277272267261254
16°F326315309304300296291284276

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
5,181
Cooling degree days, base 65°F
977
Growing degree days, base 40°F
5,791
Growing degree days, base 45°F
4,530
Growing degree days, base 50°F
3,419
Growing degree days, base 55°F
2,458
Growing degree days, base 60°F
1,644

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,05803
February89503
March752026
April4048128
May15950360
June23190618
July0329794
August2275738
September58112504
October31913195
November611042
December90208

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 6.2 km from Elsmere. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00079605 (Wilmington Porter Rsch). Public domain.